Evidence from cardiovascular research has indicated that the cardiac sympathetic nerves play a major functional role in the control of cardiac performance. These nerves have also been shown to have specific functional and structural distribution to the heart. In the conscious animal exposed to behavioral stress the cardiovascular adjustments which occur have been shown to be a consequence of general changes in the cardiac innervations. However, the influence of specific cardiac innervations on stress induced cardiac changes has not been investigated. The objective of the research proposed in this application is to describe the role of specific cardiac sympathetic nerves to cardiac adjustment during controlled behavioral stress. It is believed that through this strategy it is possible to gain a better understanding of neural control of the heart and stress induced pathophysiological states.